Air pollution accelerates brain aging

If you live in a highly polluted area, your brain might be aging at a faster rate than it normally would, according to a new study. Conducted by researchers at the University of Southern California (USC), the study found that elderly women who were exposed to high levels of air pollution showed more signs of brain aging than those who lived in areas with cleaner air. This is a landmark study because whereas past studies had demonstrated links between air pollution and the vascular system, this is the first to link pollution directly to brain damage.

The researchers analyzed data from 1,403 women between 1996 and 2006. By the end of the 10-year period, study participants' ages ranged from 71 to 89. MRI brain scans were conducted to determine the volume of the women's brains, and residential histories and corresponding air pollution data were used to measure the women's exposure to pollutants.

The results showed that for every 3.49 micrograms per cubic centimeter increase in the women's exposure to pollution, their brains' white matter shrank by 6.23 cubic centimeters. According to the researchers, this amount of shrinkage is equivalent to one to two years of natural brain aging. The connection between air pollution and white matter shrinkage existed even when the researchers controlled for variables like education and physical activity levels.

"This tells us that the damage air pollution can impart goes beyond the circulatory system. Particles in the ambient air are an environmental neurotoxin to the aging brain," said lead researcher Jiu-Chiuan Chen, M.D., of the Keck School of Medicine at USC.